Virtual Reality

Original Editor - Laura Tighe

Top Contributors - Yousef Maged Saadeldin Mohamed, Laura Tighe, Youssef Maged Saadeldin Mohamed, Kim Jackson, Vidya Acharya, Rucha Gadgil and Khloud Shreif

Background

Recent advancements in virtual reality VR technology have opened up life-changing possibilities in the field of rehabilitation. VR is increasingly being integrated into physical therapy and rehabilitation programs, providing innovative ways to help patients recover from musculoskeletal disorders and neurological disorders, and is even widely used in the geriatric and paediatric departments.

VR development in rehab is divided into 4 periods

Virtual Fixtures immersive AR system developed in 1992

Period 1 (1996-2005): The beginning of use of VR in rehab was revolutionary, where it was used in different clinical trials on stroke patients, motor disorders, pain management, and kinematic analysis. Despite the benefits, the clinical importance wasn't certain due to their high cost, technical complexity, and limited access to hardware and software.

Period 2 (2006-2014): This period was characterised by the development of clinically accessible applications, producing better technology at lower costs.

Period 3 (2015-2018): This marks the significant advancement of clinical research in VR rehab with the increasing accessibility to embedded technologies such as cameras, sensors, haptics, and wearable devices, allowing monitoring the motor and cognitive functions in real-world conditions. ^[1]

Period 4 (2019-recent): The COVID-19 pandemic accelerated the adoption of VR into remote and home-based therapies; patients needed an alternative to in-person sessions.

During the pandemic, VR remote rehabilitation became quite indispensable. While patients performed guided exercises in virtual environments, clinicians tracked progress from afar with systems tracking motion. Such a remote application was in response to the challenges presented by lockdowns and social distancing with the aim of ensuring continuance of care in cases involving injured patients, surgical recoveries, and neurological conditions.

Further developments since the pandemic have included increased haptic feedback, enabling patients to "feel" resistance in virtual settings and recover better from motor skills. Even

more personalised and adaptive therapy programs have been possible with further integration of AI. More access to cheaper VR headsets also made these technologies available for home-based rehab.

Definition

Virtual reality (VR) can be defined as the “use of interactive simulations created with computer hardware and software to present users with opportunities to engage in environments that appear and feel similar to real-world objects and events”^[2].

Virtual Reality enables the creation of a virtual environments in which immersion and interaction produce a sense of reality, where users engage and explore virtual environments in real-time. The content of these virtual environments can be created for specific purposes, such as gaming or education for example. The virtual reality technique is currently widely used in clinic and telerehabilitation^[3].

Use as a Treatment Modality

The use of VR in healthcare is increasingly supported by research evidence. Examples include burn injury management^[4], upper limb rehabilitation post stroke ^[5] and treatment of mental health disorders ^[6]. Immersive VR interventions may also have a role in musculoskeletal management and rehabilitation, although more research is needed to guide clinical practice^[7].

Common devices used in VR rehab


Device	Company	Description
Oculus (Quest 2)	Oculus VR	3D positional audio, 6 DOF sensor to track head movement, higher resolution, no cable connections.
Oculus (Rift S)	Oculus VR	Software library and easy setup with a PC hardware platform.
CAREN	Motek Technologies	Real-time motion and force capturing system, 6 DOF moving platform, 360-degree theater system.
Samsung Gear VR	Samsung Electronics Co., Ltd.	Turns a cell phone into a portable VR system; lightweight.
Psious	Amelia Virtual Care	Focuses on modules for mental health.
Virtualis	Virtualis VR (Perols, France)	Provides modules for various health conditions to improve ADL, balance, motor function, hemineglect, cognition, and proprioception.
Nintendo Wii variations	Nintendo Co., Ltd.	VR experience through player’s avatar; captures motions using a handheld device and infrared sensors.
Kinect for Xbox 360/One	Microsoft Corporation	Provides an immersive experience where individuals use their body to control game motions.
Reh@City	Teresa Paulino, Universidade da Madeira	Navigate a city and engage in basic ADLs.
BTS Nirvana VR	BTS Bioengineering	Provides rehabilitation modules specific to neurological disorders.

Mechanism of action

The exact mechanism of action of VR analgesia is not well understood but investigators have found that, there is a complex interaction of the brain cortices, neurochemistry, as well cognitive, emotion, and attentional process.^[8]

Several theories have been introduced to explain the effect of VR analgesia

Gate Control Theory demonstrating that attention to pain modifies suffering, and distractions could reduce suffering related to pain.^[9]

Multiple resources and Mental workload which refers to the various cognitive and perceptual processes that need to be used to perform a task. This theory supports the use of VR technology as a method of pain relief, which is based on integrating multimodal (visual, auditory, tactile, and olfactory) sensory distractions.^[10]

Neurobiology of Virtual Reality Pain Attenuation This theory hypothesized that VR associated analgesia arises from intercortical modulation among signalling pathways of the pain through memory, attention, auditory, touch, visual emotion inputs^[8].

It also proposed that the decrease of activities in pain matrix (e.g., thalamus, insular cortex, and mid-cingulate ACC) might be accompanied by increase of activity in anterior cingulate cortex and orbitofrontal regions of the brain (Pain processing centres)^[11]

Behavioural health According to this theory they speculated that VR works like the functioning of the brain by creating an embodied simulation of the body in the world to represent and predict actions, concepts, and emotions.^[12]

Brain rewiring

Neuroplasticity

Neuroplasticity refers to the ability of the brain to change through the formation of new neural connections. It contributes a lot towards the recoveries of motor and cognitive functions post-stroke. Parts of the brain involved in the regulation of motor activities, planning, and sensory feedback are activated as the enriched environment of VRBR reinforces old pathways or creates new ones. These, in turn, result in the recoveries of certain lost abilities after a stroke.^[13]

Motor Learning

VR based rehab(VRBR) uses principles of motor learning in regaining motor function in the patient. Repetitive, task-oriented exercises within the VR environment relate immediate feedback concerning movement to the patient. Such movements enable the brain to make error corrections and practice in a fashion that will strengthen the motor pathways. The immersive experience provided by VR maintains the patient's interest, allowing for continuous practice, which is very important for rewiring the brain.^[13]

Task-Oriented Training

The VRBR impact will be in realistically simulating scenarios wherein patients can practice activities of daily living within a controlled environment. Repetitions of the same in goal-oriented tasks bring about better motor control, faster recovery of functions such as reaching, grasping, or walking. This challenge induces the brain to adapt by constantly adjusting the difficulty level as the person improves, thus embedding new connections firmly.

Ecological Systems Theory

We can relate VRBR to ecological system's theory by noting that development is being worked through the patient's interaction with the environment. The VR environments can be personalised to represent real-world tasks, which are meaningful to the individual's goals; personally relevant practice helps in the further training of the brain in adaptation to the new task, so that skills learned in VR are transferred to daily life.

Briefly, VRBR augments neuroplasticity-based brain reorganization through engaging the stroke-survivors in repetitive and directed exercises promoting development and strengthening of new neural pathways all the way to functional improvement.

Types of VR

Non-immersive VR

Allows the user to view and interact with a computer-generated image of themselves on a screen. The user can see and experience the real world outside of the screen and is not immersed completely in a virtual world ^[7]. An example would be a gaming console such as an Nintendo Wii.

Semi-immersive VR

A more advanced visual display (panoramic or curved screens to create a greater sense of immersion) is used. Similar to non-immersive technology, the user can see the real world either side of the screen.

Immersive VR

A headmounted display unit is used, this offers a multi-sensory experience for the user. Additional equipment may include; gesture-sensing gloves, wands, vibrotactile platforms and multidirectional treadmills. All this makes it possible for the user to explore and interact with the virtual world as an avatar (a virtual character that represents the individual within the virtual world)^[7].

Embodiment is achieved when a user is immersed in VR and processes the avatar’s movements as though they are the users own body parts. To maximize this, the VR user must experience a sense of the following; location, agency (performing an action/ intervention that produces an effect) and body ownership (the user believes they are the avatar) ^[14].

Examples

Non-Immersive VR

This video shows a stroke patient using a non-immersive VR setup (Gaming Screen) to practice motor control. In this example the patient is playing a game of football, his leg movements are mirrored on screen.